Stephen Hillenburg, the American cartoonist who created the hit children’s TV series SpongeBob SquarePants, has died at the age of 57.

Nickelodeon confirmed the sad news in a tweet this evening, telling its followers: "We are sad to share the news of the passing of Stephen Hillenburg, the creator of SpongeBob SquarePants.

"Today, we are observing a moment of silence to honor his life and work."

Former marine biology teacher Stephen had worked on SpongeBob since 1999, and it still runs to this day.

Stephen Hillenburg at The Spongebob Movie: Sponge Out Of Water world premiere
(Image: WireImage)

He was diagnosed with motor neurone disease – also known as Amyotrophic lateral sclerosis (ALS) and Lou Gehrig’s disease – in his fifties, confirming the condition in a statement issued in March 2017.

"I wanted people to hear directly from me that I have been diagnosed with ALS," he said at the time.

"Anyone who knows me knows that I will continue to work on SpongeBob SquarePants and my other passions for as long as I am able. My family and I are grateful for the outpouring of love and support.

"We ask that our sincere request for privacy be honoured during this time."

Spongebob Squarepants has captivated children for the last 19 years
(Image: Press Association)

At the time, sources close to him said they believed he was in the early stages of the terminal disease, which affects mobility and motor function by targeting the nerve cells in the brain and spinal cord.

He has been described by colleagues as "a perfectionist workaholic" and once revealed why he didn’t love the spotlight.

"I make animation because I like to draw and create things. I have no real interest to be on camera or to be a celebrity. It’s not that I don’t like people, but I like having my privacy," he said.

Stephen leaves behind his wife Karen Hillenburg and their 10-year-old son Clay.